Hi Roy,
I do understand how difficult this is, I think I just have an excepting nature is why I might get it more easily. But let me take a stab at this for you.
As you know God is the creator and sustains all there is and this automatically makes Him responsible for whatever happens. So He has a plan and in this plan He determined that human beings that He created required an experience in evil as a backdrop. Now that was so that when He would eventually show us righteousness we would have this backdrop of evil to compare it to and therefore understand it's goodness better. But what we do is indeed caused by our weak carnal nature and His creating us this way was not a sin in and of itself. But He does take responsibility for creating us this way and will rectify this completely. But it is our own weak nature created within us that desires for and is actually carrying out our own lusts... I guess that would be the rotten board. But the rotten board is not evil in and of itself, it did not start out as a rotten board, it's the nature of things that it became that way. Just like a piece of wood cannot remain perfect, all physical things must come to an end, so it will rot away. Because God made it so that all physical things will not last, is not evil. But He does take responsiblity for that.
Now carry this same analogy to human beings, we were created to be too weak to resist temptations to sin, that the nature of the way we were created. But God does not do the tempting, because it's built in, it's automatic.
James 1:13 Let no one say when he is tempted, "I am tempted by God"; for God cannot be tempted by evil, nor does He Himself tempt anyone.
James 1:14 But each one is tempted when he is drawn away by his own desires and enticed.
Just like a piece of wood rots, it's our nature to sin, "it's OUR desires." It was not evil for God to create us this way and He is responsible for that. But we are accountable for our own words and deeds, He did create within us the weak natural for us to sin, but He does not do the sinning Himself, WE do, therefore we're accountable.
And also there is no need for God to tempt mankind, because He has created beings (Satan and the demons) just for that purpose, to cause temptations in the world for this evil experience we must have. It was not evil for God to create beings eager to tempt mankind to sin either, it was a necessary part of His plan.
1Peter 5:8 Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour.
All of this being as it is we know there is a good outcome for all of humanity, the few now, but the rest later.
1Peter 5:9 Resist him, steadfast in the faith, knowing that the same sufferings are experienced by your brotherhood in the world.
v. 10 But may the God of all grace, who called us to His eternal glory by Christ Jesus, after you have suffered a while, perfect, establish, strengthen, and settle you.
v. 11 To Him be the glory and the dominion forever and ever. Amen.
1John 4:14 And we have seen and testify that the Father has sent the Son as Savior of the world.
I hope this was of some help.
mercy, peace and love
Kat